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De-normalization for performance tuning

d27m11y
d27m11y asked
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Do we use de-normalization for performance tuning. If so, can someone provide me a good example how it helps.

Appreciate your help
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Most Valuable Expert 2011
Top Expert 2012

Commented:
rather than joining data from 2 or more tables,  you simply read data from one larger table.

less io,  less cpu , less temp space for sorting/hashing, etc.


downside is the updating of the data within denormalized sets.  That's why they are typically used for reporting purposes, and not transactional storage
Most Valuable Expert 2011
Top Expert 2012
Commented:
example, using the standard SCOTT example schema

ee.txt

You could also check this article: "The Dangerous Illusion: Denormalization, Performance and Integrity"

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Commented:
thanks!
Most Valuable Expert 2011
Top Expert 2012

Commented:
why the B?  what was missing/wrong?

if you needed more info, please ask before assigning penalty grades